<div dir="ltr"><div><div>Dear all,<br><br></div>Below is an abstract for APS April Meeting. <br></div><div>Comments are welcome. <br><br></div><div>Thank you,<br>Vahe<br></div><div><br></div><div><div><div><div><br> Simulation of a hadron calorimeter for Jefferson Lab Hall-A Super Bigbite Spectrometer<br>
<br>A “shashlik” hadron calorimeter is being designed for the new Super Bigbite Spectrometer in<br>Jefferson Lab Hall-A. The calorimeter will be used in coincidence-nucleon form-factor experiments<br>after Jefferson Lab's 12 GeV upgrade. It is being optimized to detect hadrons in a momentum range of<br>
2-10 GeV/c and provide high hadron-detection efficiency with excellent time and spatial resolution.<br>Ongoing work is focused on optimizing time response by exploring unconventional scintillator and<br>wavelength shifter (WLS) materials.<br>
A Geant4 simulation has been developed to optimize energy, position and time-resolution and hadron<br>detection efficiency of the calorimeter. Significant efforts were made to implement the simulation as<br>realistically as possible. Optical properties, decay times and light yield of the scintillator and the<br>
wavelength shifter were included in the simulation. Optical photons were tracked inside the WLS-lightguides<br>taking into account surface properties of the light guide. Quantum efficiency of the PMT was<br>also included. In order to correctly simulate the response of the PMT, actual single photo-electron<br>
(SPE) waveforms were measured and used to form the cumulative response of the PMT. The simulated<br>signal is a sum of all waveforms with corresponding arrival times. The response of the PMT is saved in<br>a ROOT file and analyzed to extract detector-response time resolution.<br>
Simulation has been validated by measuring detector-response time resolution for cosmic ray muons in<br>hadron calorimeter blocks of a similar design used in the COMPASS experiment. It was found that the<br>simulation was able to predict response time resolution for the cosmic ray muons with 5% precision.<br>
Another test with ELJEN 232 scintillator and ELJEN 299-27 WLS combination was conducted to<br>study their suitability for use in the hadron calorimeter as well as to validate the simulation. The results<br>of that test indicate that this combination is suitable for the hadron calorimeter and the simulation is<br>
able to predict time resolution with better than 5% precision.<br> In conclusion, simulation predicts ~1.5 ns FWHM time resolution, 5-3 cm spatial resolution and more<br>than 90% hadron detection efficiency.<br><br></div>
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